Analysis - Brown seeks compromise on embryo bill

Gordon Brown has announced a compromise on the human fertilisation and embryology bill, after weeks of speculation over whether Labour MPs would be whipped into supporting the bill.

The timing of the announcement will do little to dispel Mr Brown's reputation as a ditherer, coming after a prolonged period of uncertainty.

It is argued that Mr Brown delayed making a decision because Labour whips were sceptical the government would be able to pass the legislation under a free vote.

The prime minister finally confirmed Labour MPs will be given a free vote on the most controversial aspects of the bill after an Easter weekend which saw Church leaders step up their opposition to the legislation.

The ongoing debate of science versus religion has seen the bill challenge forthcoming plans to extend the period for detention without trial to 42 days for the title of most controversial piece of legislation in this parliament.

Ministers have slowly become more vocal in defending the bill, which draws together a wide range of existing legislation and regulation to update the UK's law on reproductive technology and embryo research.

Mr Brown today said the stem cell research enabled by the creation of hybrid embryos could "hold the key" to curing diseases including Alzheimer's, Parkinson's and even heart disease.

Keen to dispel the notion of playing politics with ethical and scientific issues, Conservative leader David Cameron has now also spoken of the therapeutic potential of the legislation.

Political pressure from the opposition has been focused purely on Mr Brown's supposed dithering over whether to allow a free vote.

Despite the apparent climb-down from the government, it remains unclear whether Mr Brown's compromise stance will head off a rebellion.

Catholic MPs and others with moral objections will be allowed to vote against the creation of hybrid embryos, so-called saviour siblings and IVF reforms benefiting same-sex couples and single women in the debate stage of the bill.

But Mr Brown has said a three-line whip will be enforced when the bill has its second and third reading in the Commons.

This raises the prospect that, if the government is successful in getting the bill accepted in its entirety, MPs who voted against the three measures will be whipped into supporting them in the bill's final readings.

Ministers are said to be taking the calculated decision many MPs will be satisfied if given the opportunity to "let off steam", although it is uncertain whether a hotly-debated conscious issue will cease to be so morally unacceptable by the third-reading.

Mr Brown has faced the threat of losing three Catholic Cabinet members over the bill, including transport secretary Ruth Kelly.

Such a shake-up to the government would harm Labour when it is weak in the polls and it can be argued the loss of Peter Hain exposed the lack of experienced Labour MPs ready to take on Cabinet responsibility.

Regardless of whether Mr Brown's compromise succeeds in heading off a Labour rebellion, the bill is not set to have a smooth passage through the Commons.

Despite being intended to update legislation on scientific research and IVF, anti-abortion campaigners are set to attempt to use the bill to reduce the abortion time limit to 20 weeks.

Mr Cameron has joined anti-abortion stalwarts Ann Widdecombe and Nadine Dorries in pledging to vote for such an amendment, in a bold statement on women's rights from the Tory leader.

Downing Street has said the prime minister has now plans to back any reduction to the limit, pointing to the lack of scientific evidence supporting such a move.